Downdraft hot-air furnace



Feb. 22, 1927.

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/QTTO/PNEF l Patented Feb. 22, 1927. I

UNITED; STATES PATENT orties.

CHARLES W. SWINGLEY AND HARRY IYIELLER, OF ST. LOUIS, MISSORI.

DOWNDRAFT nor-AIR resulten* Application filed February`i2, 1926. Serial No. 87,860.

This invention pertains toair heating furnaces,` particularly those of the domestic. type. f

One of the objects of this invention is to provide an improved type of air heating furnacein ywhich the down draft principle of combustion of the fuel may be employed.

Another object is to provide such a furnace having improved facilitiesfor bringing the air to be heated in Contact with the heating surfaces.

Further objects will appear from the following description taken inconnection with the accompanying drawings in which:

Figure 1 is a front view of a furnace embodying this invention;

Figure 2 is a plan view partly in section of the same; and

Figure 3 is a side view'ofthe same, showing parts in section.

In the accompanying drawings, 1 desig-v nates a fire box which maybe constructed of cast iron or other suitable material and which has mounted therein an upper grate 2 and a lower grate 3. The lower grate may be of any suitable construction well known in the art. The upper grate 2 .is constructed of a series of parallel tubes, running from front to rear of the fire box, and preferably inclined slightly upwardly toward the rear. The furnace may be provided with clean-out doors 4 and 5 providing access respectively to the space over the grate 3 and to the ash pit. i

A firing door 6 is provided above the upper grate 2. The fuel is supplied through this door to the upper grate. After partial combustion upon the upper grate, during which the volatile ingredients of the fuel are usually given off, the coal. in the form of coke, drops through the upper grate to vthe lower grate. On the lower grate the coked fuel completes its combustion, after which the ashes fall through to the ash pit. i The ring door 6 is provided with an air inlet 7 having a damper of any suitable design and through which air for combustion of the fuel is admitted. This air passes over the upper grate 2 and downwardly therethrough. During this passage it supplies oxygen to the fire on the upper grate and also carries the unburned gases produced thereby downwardly to the lower fire. During the progress of the air over the lower grate it supplies oxygen for the combustion of the coke on that grate and also carries the unburned gases into contact with the lower fire by which they are completely consumed, so that the furnace operates practically without smoke. After passing over the lower hre-bed, the gases pass out through a flue opening 8 to the smokestack 9. A clean-out 10 connects with a clean-out door 11 for .the removal of the soot deposits.

Surrounding the fire box 1 is a jacket 12. This may be constructed of cast iron, fire brick or any other suitable material. -A space' 13 is left between the fire box land the acket 12 for the circulation of the air to be heated. The front of the furnace is provided with openings 14. having `dampers 18, for thev admission of the air to'be heated, which circulates through the space between thefire box and the jacket so as to come in contact with the heated surfaces of the fire box and then passes to the rear 'of the jacket and out to the air distributing system by means of the hot air pipes 15. The frontof the furnace 'may also be provided at its upper portion with oneor more inlet openings 16 provided with suitable dampers 17 through which air may be admitted at the f top when desired.

The hollow grate bars of the upper grate 2 extend through the front and rear of the fire box and are open. at both ends. They are therefore adapted to receive air from the front of the furnace carrying the same Vthrough the heated tubes and delivering it to the rear portion of the jacket and eventually to the pipes 15. The rearward and upward incline given to these pipes causes the heated air to fiow upwardly therealong so that a continuous draft of air is passing through said pipes. This draftrserves not only to heat the passing air,but also to cooll the` Valso through the hollow grate bars so that a great quantity of air at a high temperature is delivered to the distributing system.

It is obvious that various changes may be made in the details of construction withe :sa

out departing from tbe spirit ol this inven tion; it is to be understood, therefore, that this invention is not li1nite l to the speeilic details shown and described.

Having thus described `[he invention, what is claimed is: e

l. A clown draft furnace comprising a lire box, an upper grote, a lower grate, a ilralt inlet to Said lire box above seid upper grate, an outlet from said lire box below said upper grate, an air jacket einroniub ingsaid lire box and a smoke tine within said jacket and eonnecting` with saicl outlet. l

Q. An air heating 'furnace comprisnee` a lire box havingI ite outlet et tbe lower part thereof, and a fine leerling therelronr. an upper grate above Said outlet, a lower irate below said outlet atluptell to ree-cire i'nel from said upper grate, a tlrailft inlet to mill lire box above Said upper grate, an air jacket surrounding said lire bei; :nul line anal prrr "vided with an air inlet, and air dielrilniting; means connected with Sani jacket :mtl receivingr the hot air therefrom.

3 A11 air heating; fnrnaee coniprieing; :i Alire box having1 its outlet at the lower part thereof end :t {lue leading therefrom, an upper grate above said outlet, a lower grate below said outlet adapted to receive lnel troni said upper grate, a ilre'l't inlet to eaitl lire box above said upper grate, an :if jacket coextensive with Said lire box :nljaeent said gratesand enclosing; eaitl liuc and provided with an air inlet, and air clis- Leieie ei-ate` :i (b'alt inlet to said lire box above will opper grate, an outlet from said lire bof-z below said upper grate and a flue leading;l therefrom, air distributing means around :mill ilue receiving air from said hollow grate elljaeent the flue. i

iin air heating :furnace comprising' a lire box. an upper grate, a lower gratte, a .lrel't inlet to said lire box` above said upper grate. an outlet ifi-oni said lire box below mid upper grate, an air jacket surrounding; muil. lire box, an air inlet for said jacket at the 'liront o' the furnace above :Said lire bex, anni air distributing means connected with eanl jacket and receivingr the hot air tberelroin.

o. in air heating furnace comprising a lire bei:` an upper grate, `a lower grate a li-att inlet to said fire box above said upper grate, an outlet from said lire box above wahl, upper girate, an air jacket euirrountlingr .Liaitl lire boit, an air inlet for Said jacket at the :lfront oil the Yfurnace above said tite box; ineens 'lor controlling the flow ol air through snitl jacket, and an air distributing mean` eonneeted with said jacket and receiving' the hot air tlierelroin.

,ln teetinlon)v Whereoi' we allix our signatures.

CHARLES W. SWINGLEY. HARRY MILLER. 

